Physical Activity in Older Adults: The Role of Intentions, Executive Control Resources, and Implementation Intentions

Abstract

Objective: The purpose of this investigation was to examine the effect of implementation intentions on physical activity in older adults with stronger and weaker executive control resources (ECRs). Methods: One hundred and ten community dwelling older adults (Mage=74.42) were randomly assigned to receive either a physical activity implementation intention intervention, a control intervention, or no-treatment. Three ECR facets (inhibition, task-switching, working memory), baseline behaviour and baseline intentions were assessed during the initial laboratory session. During 4 weekly follow-up telephone interviews, participants reported physical activity behaviour for the previous week, and refreshed implementation intentions for each upcoming week. Results: A main effect of treatment condition on 1-month self-reported physical activity was observed, with those in the experimental group reporting significantly higher physical activity than those in the control or no-treatment conditions. In addition, a significant 2-way (intention strength by treatment condition) interaction emerged, with the experimental group showing higher intention-behaviour correspondence than the control and no-treatment groups. A marginal 2-way interaction of intention and behavioural inhibition was also detected; those with stronger behavioural inhibition had higher intention-behaviour correspondence relative to those with weaker behavioural inhibition across all three treatment conditions. Conclusions: Implementation intentions are effective in facilitating physical activity in healthy older adults. The findings also indicate that behavioural inhibition may be important for the moderation of intention-behaviour relationships in the context of physical activity, regardless of goal setting strategy.